Aldehydeamine cinchona bark alkaloid condensation product



Patented Aug. 15, 1933 cRoss REFEREtCE "ALDEHYDEANHNE CINCHONA BARK ALKA-f LOID CONDENSATION PRODUCT fl c Ralph E. Lawrence, Wickliife, Ohio, assignor to The Grasselli Chemical Company, Cleveland, Ohio, a Corporation of Delaware No Drawing. Original application December 19,

1931, Serial No. 582,187. plication November 22, 1932.

2 Claims.

This invention relates to novel substances useful for the control of the action of acids upon metals in pickling and other metal cleaning operations.

It is known through U. S. Patent No. 1,742,986, H. P. Corson, January '7, 1930, that chinchona bark alkaloids have the properties of inhibiting the action of acids upon metals and U. S. Patent No. 1,719,649, G. D. Chamberlain, July 2, 1929, discloses that aldehydeamines have these same properties.

I have found that by reacting with cinchona bark alkaloids upon aldehydeamines, new con- 5 densation products are obtained which have to a greatly enhanced degree, the property of inhibiting the action of acids upon metals and my invention comprises the novel condensation products obtained by heating to temperatures above about 100 an aldehydeamine and a cinchona bark alkaloid and their application to processes of cleaning or pickling metal articles involving the action of dilute, non-oxidizing acids upon metal articles.

Aldehydeamines have been produced from various aliphatic and aromatic amines condensed with aliphatic and in a few instances aromatic aldehydes. They are known in various molecular ratios of aldehyde to amine. The primary, di-

rect-reaction products are further known to react with further amounts of amine or with sulfur and hydrogen sulfid to produce substances of properties somewhat similar to those of the primary products. Very few aldehydeamines have been obtained in crystalline form and their chemical constitution is in most instances undetermined. These aldehydeamines have both chemically and physically very similar properties and a majority of them are known to ac- 49: celerate the sulfur vulcanization of rubber.

Cinchona bark contains a number of alkaloids of which quinine, q 'nidine, ci honine for instance are mined an used in medical arts. After extracting these important, crystal- 455, line products from the crude alkaloid mixture contained in the bark, there is left an amorphous complicated mixture of substances of alkaloidal character which is known as quinoidine.

I produce my novel inhibitors by heating to- 59, gether an aldehydeamine chosen from the large all; of these products.

Divided and this ap- Serial No. 643,953

In view of the complex nature of the components used to prepare my novel condensation products, I have been unable to develop any theory as to the formation of my novel inhibitors or to establish their chemical constitution. Even when using relatively small but substantial amounts, say for instance 10% of the total, of an aldehydeamine and heating it with for instance quinoidine, I obtain condensation products which show a marked increase in inhibiting efiiciency over the alkaloid used alone or in mere physical admixture with the aldehydeamine. Different proportions of the components up to equal weights give likewise on heating condensation products of marked inhibiting efficiency. Excellent results have, for instance, been obtained with condensati ts f p 5 arts hydeamine and 11 5 parts quinoidm' e or other cinc ona bark allgglg The similarity of chemical properties of aldehydeamines is also shown in my novel reaction. I have condensed various aldehydeamines with cinwjgs and in all instances obtaine inhibitors of efilcient inhibiting properties. The selection of the raw materials for producing practically useful inhibitors is, therefore, entirely dependent upon economical considerations and condensation products of acetaldehydeaniline with quinoidine are not only easily available but have an efficiency of over 95%, when comparing pickling baths without or with the addition of even less than for instance 0.1% of the condensation product.

The condensation is effected by heating the mixture of the components to above 100 C. when an exothermic reaction takes place. The melt is kept for a short time between about 130 to 140 C. On cooling, a solid dark, resinous mass is obtained which can be used directly.

The resinous, yellowish to brown colored condensation products are easily and nearly completely soluble in dilute sulfuric or other acid, seemingly without decomposition and this easy solubility is a great advantage in pickling and cleaning operations.

Dilute, non-oxidizing acids, such as sulfuric, hydrochloric, phosphoric, acetic, formic are commonly used in pickling and metal cleaning operations. Dissolving small amounts, for instance,

from 0.05 to 0.5% or even less, of my novel condensation products in such acids, produces cleaning baths which are as efficient in removing oxides, scale or other impurities from metallic surfaces as the straight acids, without, however,

EXAMINER loid which is a yellowish-brown, resinous material, easily and at least nearly completely soluble in dilute sulfuric acid and which has the property of inhibiting the action of acids upon metals. 2. As a new compound the acetaldehydeaniline-quinoidine heat condensation product which is a yellowish-brown, resinous material, easily and nearly completely soluble in dilute sulfuric acid and which has the property of inhibiting the action of acids upon metals.

. RALPH E. LAWRENCE. 

